Well, I made a crappy sodium ampoule today (the other ones kept breaking). However, the sodium is not in one piece: Formerly molten blobs are
scattered up and down the tube. Is there a good way to melt sodium (without resorting to a blowtorch) in a sealed ampoule? I tried melting under water
(sodium's MP and water's BP are roughly the same), and mineral oil. Neither worked.Adas - 8-4-2013 at 06:51
Maybe it is too impure, if it didn't work.Finnnicus - 8-4-2013 at 06:59
Radiant heat? Like some sort of super overpowered heat lamp?elementcollector1 - 8-4-2013 at 07:46
Hmm. I bought it from United Nuclear a while back, and most of the metal in there is shiny. I'm beginning to think that it's the solvent that's been
causing problems, as whenever the blowtorch touched the sodium, it melted into a blob stuck to the tube (think capillary bubble of air) and moved
*up*. Gas being produced from the solvent boiling, most likely.
At least the ampoule seal is fine - for now...
Quote:
Radiant heat? Like some sort of super overpowered heat lamp?
I do know a place to get infrared LED's, but I don't think they could reach 100 C easily. Finnnicus - 8-4-2013 at 08:12
I was thinking more along the lines of a bulb, not leds. But that doesn't help anyway.Endimion17 - 8-4-2013 at 09:54
It melting point is ~98 °C. If it doesn't melt in 150 °C hot oil, it isn't exactly sodium, though I think I know what's the problem here. There was
moisture inside and it created sodium hydroxide which reacted with the glass. Now what looks like sodium is sodium covered sodium silicate.
Blowtorch? What the hell is with all these blowtorches all of the sudden? Glassware is heated by blowtorches when it's being modified. People, buy
Bunsen burners. They were around for more than 150 years.
I cringe when I see "youtube chemists" heating test tubes and flasks with thin, fierce blue flame from blowtorches. Nurdrage did it
several times with regular glass vials and he should know better.elementcollector1 - 8-4-2013 at 10:19
It's sodium, I'm sure of that much. The blobs are silvery, and behave much like liquid metal when melted (except for that odd capillary effect).
I use a blowtorch because I have a blowtorch. If I had a Bunsen, I'd likely be using that instead.Endimion17 - 8-4-2013 at 11:07
At least reduce the air intake. That's what I do with mine. I use a gentle breeze of propane and barely enough air to get a gentle flame.
Narrow, laser-like blue flames are the best way to gradually fuck up expensive glassware or to cause sudden cracking.
Maybe your sodium appears solid because the blobs are tiny and the metal has high surface tension. Heat it to 150-200 °C and then use the same motion
as when resetting a medical mercury thermometer. A centrifuge would help a lot.
